Stepped surfaces are widely present in nanoparticle catalysts and exhibit unique catalytic activity. In this study, we systematically investigated the structural and dynamic properties of the Pt(211)/water interface system under different \(\textrm{OH}^*\) coverages and temperatures using deep potential molecular dynamics (DPMD) simulations. The results reveal that the interfacial water molecular density distribution, orientation, adsorption behavior, and hydrogen bond network are significantly influenced by both \(\textrm{OH}^*\) coverage and temperature. As \(\textrm{OH}^*\) coverage increases, water molecules tend to adsorb with their oxygen atoms oriented away from the surface, while the number of surface-adsorbed water molecules increases. This leads to a transition in the water dissociation mechanism from direct dissociation to adsorption-followed dissociation. Furthermore, elevated temperature promotes water dissociation but reduces the stability of hydrogen bond networks, thereby affecting proton transfer efficiency to the surface. The potential of zero charge (PZC) of the interface electrode gradually shifts negatively with increasing \(\textrm{OH}^*\) coverage, indicating a lower onset potential for the hydrogen evolution reaction (HER) at higher coverages. The findings demonstrate that increasing temperature and \(\textrm{OH}^*\) coverage can enhance water dissociation while simultaneously reducing proton transfer efficiency. Since the rate-determining step for alkaline HER is water dissociation, the overall effect of elevated temperature and \(\textrm{OH}^*\) coverage accelerates HER kinetics. These results provide molecular-level theoretical insights for optimizing the design of hydrogen evolution reaction catalysts.
